Hey, good luck with the entry! There a number of cool software made for sound generation: http://www.bfxr.net/ and http://drpetter.se/project_sfx...
bfxr is a glorified sfxr according to description.
if you are more into music then sunvox and lmms might be useful. http://www.warmplace.ru/soft/s... https://lmms.io/
I am only starting learning music so I probably can't make anything reasonable yet ;) Good luck